One of the next-generation candidates for electric power generation is a fuel cell. A fuel cell generates electric power by direct electrical power generation from a fuel and oxidizer in a manner similar to a battery. A fuel cell generally uses hydrogen and/or carbon based fuels, e.g., natural gas, hydrogen, methanol, coal (i.e., for a direct carbon fuel cell). The fuel is generally in a liquid (e.g., a direct methanol fuel cell) or gaseous form, although solid fuel (e.g., a slurred mixture of coal) has been used in some experimental fuel cells.
Fuel cells are used in fuel cell modules and fuel cell apparatuses comprising fuel cell modules. One example of a fuel cell module comprises a fuel cell stack housed in a rectangular parallelepiped housing. A fuel cell stack generally comprises a plurality of fuel cells that are juxtaposed to each other, electrically coupled in series, and attached to a manifold. Some fuel cell modules comprise a plurality of fuel cell stacks in a housing. In such fuel cell modules, a heat insulator may be positioned between fuel cell stacks.
When generating electricity with a fuel cell module or fuel cell apparatus, a fuel cell stack generates heat. Heat resulting from the generation of electricity is dissipated from between adjacent fuel cells. Although fuel cells positioned at the ends of a fuel cell stack in the direction in which the fuel cells are arrayed (array direction) can more easily dissipate heat, fuel cells positioned around the central portion cannot easily dissipate heat.
Accordingly, there is a need for fuel cell modules in which a temperature distribution of a cell stack is closer to uniform.